In modern day steel mills or hot rolling mills the progress of the hot metal products being worked or conveyed must be closely monitored. This is normally accomplished by the use of detecting units which detect the infrared radiation radiated from the hot metal. As previously mentioned, such detectors might be hot metal detectors, loop controllers or scanners, or optical barrier units. It is obvious if these detection units should fail that dangerous working conditions can be created in the mill and a large amount of expensive damage can be done to the metal product and to the equipment.
It is therefore necessary to periodically test the accuracy or credibility of these infrared radiation detection units. Prior to the present invention, no universal test unit has been provided to easily and quickly test these infrared radiation detection units.
These infrared radiation detection units normally include a number of relays with relay contacts that carry heavy electrical currents. These relays are either energized or deenergized to indicate the presence of certain functions, such as the initial detection or presence of infrared radiation, the presence of alarm conditions and the like. Accordingly, over a period of time these relay contacts become corroded and/or burnt thereby creating unwanted electrical resistance between the engaging surfaces of the contacts. When this resistance becomes excessive, the infrared radiation detection unit will malfunction.
It is therefore desirable to have a universal test unit which will not only determine if the radiation detection unit is capable of detecting the presence of radiation in varying intensities but will also readily test all of the relay contacts within the detection unit and do so at low voltages and currents which will not create electrical hazzards to personnel.